Cold-active endo-1, 4-β-glucanase (EglC) can decrease energy costs and prevent product
denaturation in biotechnological processes. However, the nature EglC from C. farmeri
A1 showed very low
activity (800 U/L). In an attempt to increase its expression level, C. farmeri
EglC was expressed in Escherichia coli
as an N-terminal fusion to protein S (ProS) from Myxococcus xanthus
A novel expression vector, pET(ProS-EglC), was successfully constructed for the expression of C. farmeri
EglC in E. coli
. SDS-PAGE showed that the recombinant protein (ProS-EglC) was approximately 60 kDa. The
activity of ProS-EglC was 12,400 U/L, which was considerably higher than that of the nature EglC (800 U/L).
ProS-EglC was active at pH 6.5–pH 8.0, with optimum activity at pH 7.0. The recombinant protein was stable
at pH 3.5–pH 6.5 for 30 min. The optimal temperature for activity of ProS-EglC was 30°C–40°C. It showed
greater than 50% of maximum activity even at 5°C, indicating that the ProS-EglC is a cold-active enzyme. Its
activity was increased by Co2+
, but decreased by Cd2+
, methanol, Triton-X-100,
acetonitrile, Tween 80, and SDS.
The ProS-EglC is promising in application of various biotechnological processes because of its
cold-active characterizations. This study also suggests a useful strategy for the expression of foreign proteins in
using a ProS tag.